The height: 500px; being applied to the div containing your post information is what’s causing the issue. The div is being constrained to be no more than 500px tall, and any text that extends beyond that 500px is overflowing out of the container (and overlapping the container below).
Remove the height:500px; portion from the div. That will cause the height to be set to “auto”, which means it will expand to fit the contents. If you want to make sure that the div is at least 500px tall, you could replace height:500px; with min-height:500px;, which means it will be at least 500px tall, but will expand beyond that if necessary.